Just What Are Those Bully Sticks, Anyway?

The composition of these popular dog treats - and their calorie count - may surprise you.


If you’re only learning while reading this sentence that a bully stick is a bull or steer penis, you’re not alone. Almost half of 752 people responding to a questionnaire prepared by Tufts veterinary nutritionist Lisa Freeman, DVM, PhD, DACVN also were unaware of what bully sticks are composed of. So were almost 40 percent of the veterinarians who filled out the survey. Respondents hailed from across the United States and six other countries.

The ignorance isn’t surprising when you consider that pet treat manufacturers are not required to state plainly on the label what bully sticks are composed of and instead often refer to them euphemistically as “bull pizzle” or, even misleadingly, as “cow muscle.”

But the ignorance has unintended consequences. Of the people answering the questionnaire who fed bully sticks to their dogs, more than seven out of 10 said they avoid by-products in pet food, even though, for all intents and purposes, an animal’s penis is a byproduct. And it’s raw.

That’s an important point, says Dr. Freeman, because raw treats, just like raw pet food, may be contaminated with bacteria that can cause illness not just in dogs who eat them but also in people who handle them as well as other pets in the household. Indeed, Ontario Veterinary College’s Scott Weese, DVM, DVSc, DACVIM, who worked with Dr. Freeman on the research, found that of 26 treats analyzed for contaminants, more than 10 percent contained bacteria that could potentially make dogs and people sick. These bacteria included a strain of Clostridium difficile, Staphylococcus aureus (MRSA,) and E. coli, the latter two of which were resistant to the effects of certain antibiotics.

“These findings should make us think more carefully about this type of treat and similar treats,” says Dr. Freeman. “One of the most common dog treats that gets recalled is pig ears,” she points out. “Like bully sticks and other similar treats, they’re raw, and some studies have shown high rates of Salmonella contamination in Canada and the U.S.

“You have to consider such treats the way you would a raw meat diet,” Dr. Freeman adds. “People handle these things and don’t really think about what they are. If you’re going to feed it, wash your hands after touching it, and be aware that you are feeding a food to your pet that may be contaminated with bacteria, like any meat that hasn’t been cooked.” In addition, she and her co-researchers say, high-risk individuals — including the very young, the elderly, pregnant women, and immunocompromised people — should simply avoid all contact with bully sticks and other raw animal-based treats and foods. (You can read more about raw foods for pets on the Tufts Cummings School website at http://www.tufts.edu/vet/nutrition/faq/general_pet_nutrition.html).

Calories are a big issue, too

It isn’t just the composition of bully sticks of which people are unaware, and their potential bacterial contamination. Most are not acquainted with the caloric punch these treats pack, either. Fully half the respondents to the survey said that a 12-inch bully stick contains either 70 calories, 20 calories, or zero calories. None were correct. A 12-inch bully stick has on the order of 150 calories. Indeed, when the bully sticks were analyzed for calories, caloric content ranged from 9 to 22 calories per inch, meaning that in some cases, a 12-inch bully stick contained as many as 264 calories, a large part of many dogs’ total daily calorie needs. “People vastly underestimate the number of calories in these treats,” Dr. Freeman says. Unfortunately, unlike foods for people, most foods for dogs do not have to be labeled with calorie information.

It’s a critical point because “obesity is a common problem in dogs,” Dr. Freeman, Dr. Weese, and their colleague, Nicol Janecko, write in the Canadian Veterinary Journal, where their research was just published. “Most owners do not consider treats to contain a significant number of calories” and “therefore, owners may be unknowingly providing additional calories to their dogs by feeding bully sticks.”


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